Yeast morphology in D2O

Comparison of growth in different D2O concentrations: 20% D2O on the left, 99% D2O on the right.

Yeast grown in 99% D2O.

Yeast grown in 20% D2O.

Checking on my yeast to ensure there isn’t any bacterial growth, I noticed they look very different in different D2O concentrations. In 99% D2O the cells appear larger and more circular, while in 20% D2O the cells appear to be elongated. I’ll have to grow some cells in normal water for comparison.

Also I noticed that in 99% D2O the cells seemed to form small colonies of about 10-20 cells, while in 20% D2O I saw almost no evidence of colonial formation. I also saw no yeast tea party (no? NO? oh well…). I think the colonies aren’t so much clusters as they are chains of buds, because they all seem to be attached. I didn’t analyze very thoroughly though.